Chandra X-Ray Observatory

CXC response to CUC Recommendations following 2008 Apr CUC Meeting

> The CUC continues to be extremely satisfied with the quality and
> professionalism of support that the CXC brings to the spacecraft
> operations, data systems, and the user community. The CUC is also
> extremely pleased by the responsiveness of the CXC to previous CUC
> recommendations and requests.
> On the basis of the presentations and subsequent committee discussion,
> we have a number of specific comments, suggestions and recommendations
> for the CXC.
> 1) CHANDRA SOURCE CATALOGUE : To reiterate the point already made
>    above, the CUC continues to believe that the Chandra Source
>    Catalogue is a very important part of Chandra's scientific legacy,
>    enabling qualitatively new investigations into the statistical and
>    multiwaveband properties of X-ray emitting sources.  The CUC
>    commends the catalogue team on the progress that has been made
>    since the last CUC meeting but has to admit to being disappointed
>    by yet another significant slip in the schedule (3 months delay
>    during the 7 month reporting period).
>    RECOMMENDATIONS : We renew our recommendation that the Catalogue be
>    given the highest possible priority subject, of course, to
>    critical mission operations.  We also recommend that the
>    beta-version of the catalogue be released to a limited set of
>    interested parties in order to work out any initial bugs.  The set
>    of investigators who *proposed* for (rather than won) Cycle-10
>    catalogue-related archive proposals would be one such subset.

The Chandra Source Catalog team appreciates the suggestion of the
CUC to release a beta version of the catalog to a limited set of
interested parties in order to work out any initial bugs.

The catalog release plan has always included a period, beginning
shortly after the start of catalog production and continuing to the
first official release of the catalog, during which the catalog
database and data products will be available for public use and review
through the catalog graphical user interface.  This is effectively a
beta test period open to all users.  We will strongly encourage
feedback during this time period.

Prior to the start of production we can in addition make available a
basic, static snapshot of the two primary catalog databases for the
subset of observations processed during the scheduled pre-production
test.  The products will include dumps of the master source database
and the database of individual source observations.  The associated
file-based data products will not be available, and the data may not
fully match the user documentation.  Only limited user support will be
possible without adversely impacting the catalog schedule, but we will
respond actively to any problem reports.  The level of effort required
to construct and distribute a complete beta version of the catalog
products at this time will significantly affect the catalog production
and release schedule, which is clearly not desirable.

The catalog team is committed to completing the first official release
of the Chandra Source Catalog in early 2009 (as discussed at the last
CUC meeting), preceded in fall 2008 by a period of public access to
the catalog databases and file-based data products following the
process described above.  Recent operational testing and scientific
review of the data generated by the catalog processing pipelines was
very positive and no significant problems were identified.  Although
there are several tasks involving hardware, operations, documentation,
statistical characterization, and public access that remain to be
completed over the coming weeks, the team is confident that we are
nearing the completion of release 1 of the catalog.

> 2) GRATING OBSERVATIONS : The CUC appreciates the efforts undertaken
>    by the CXC and the Director's Office in particular to gauge
>    discontent within the community concerning grating observations via
>    the gratings survey.  The CUC was also pleased to see the
>    development of TGCat, the grating catalogue.
>    RECOMMENDATIONS : Although it was suggested by several members of
>    the community via their responses to the gratings survey, the CUC
>    does NOT support a special gratings/spectroscopy panel at the
>    proposal review.  We felt that such a panel might lack the
>    topical/contextual expertise to properly assess the scientific
>    merits of a given proposal.  
>    The CUC also recommends that the CXC underwrites the support of
>    TGCat to ensure that this effort continues.
>    In terms of the gratings-related threads, the CUC feels that both
>    proposal-planning and analysis threads are important, but that the
>    proposal-planning threads should probably be given priority at this
>    stage.  The CUC also notes the importance of making these threads
>    XSPEC friendly... at the very least, they should be constructed so
>    that there is a clearly identified break-point where the user can
>    break with the thread (which will probably head down a Sherpa/CHIPs
>    path) and use XSPEC to fit the spectra.

The first priority of the HETG group has been to write threads that
represent the manner in which our group actually analyzes the data.  
This more easily allows us to answer questions based upon the threads
(although some of us are well-versed in XSPEC, none of us use it
anymore in day-to-day analysis), and it allows us to prepare users for
subsequent, more sophisticated analysis and proposal threads which by
their nature will not be XSPEC-based.  For example, we have a draft of
a proposal and analysis thread on simulating and fitting a
differential emission measure profile.  This thread is reasonably
straightforward in S-lang based analysis, but is much more difficult
using XSPEC. 

However, we agree with the CUC that it would be preferable to support
a wider base of analysis approaches.  As we revise existing threads,
and prepare new ones, we will endeavor to separate the threads at
natural break points after which users can proceed to the analysis
platform of their choice.  Our highest priority will be to establish
what we consider to be a good baseline of proposal threads that cover
the most common scenarios.  Once we establish this basic set of
threads, which we can most quickly and easily do via the non-XSPEC
paths that we routinely follow, we could establish as our next
priority generalizing them to a wider set of analysis platforms, e.g.,

Before the next CUC meeting, we will be finalizing the proposal thread
describing how to simulate and fit a differential emission measure.
Additionally, we will draft of a proposal thread on utilizing the
gratings catalog (TGCat) for proposal planning purposes.  (Final
release of this thread will occur by December.)  We plan to make TGCat
analysis products (standard PHA files, ARFs, and RMFs) available,
suitable for use in any of the standard analysis systems.
Additionally, the TGCat interactive spectral plots can also be saved
as ASCII files, and thus are also amenable for use in programs such as
IDL (and hence might be more useful to those who are less familiar
with X-ray astronomy).  The proposal planning TGCat thread will
describe these features so that non-expert users can take advantage of

> 3) CIAO : The CUC is pleased by the successful launch of CIAO4.0, and
>    the continuing efforts to educate the community about its
>    capabilities.  The CUC strongly encourages the CXC to proceed with
>    the CIAO workshop later this year.  Following on from the request
>    by SDS to the CUC last Fall, we have solicited suggestions from
>    colleagues for future CIAO improvements/capabilities.  We are
>    currently compiling the responses into a coherent form and will
>    send it to the CXC as a separate amendment to this report.

CXC is happy to report that the CIAO workshop will take place
on Oct 20-22, and numerous registrations have already been received.
We look forward to the CUC's inputs on CIAO.

> 4) SCHEDULING : The CUC applauds the sterling efforts of the mission
>    planning team to managed the increasingly restrictive thermal
>    constraints.  At this stage, we simply ask that we are kept
>    informed about further developments in the thermal constraints.

Mission Planning will provide updates at each CUC meeting on
thermal constraints when they evolve.

> 5) MENTORING OF CHANDRA FELLOWS : While the CUC strongly supports the
>    mentoring of younger members of our community, a mandated program
>    of institutional mentors for Chandra Fellows seems heavy handed and
>    may not ultimately be that successful.  Furthermore, after
>    informally consulting some previous Chandra and Hubble Fellows it
>    appears that such a requirement may even be viewed as a slight
>    insult to these highly successful and motivated individuals.
>    RECOMMENDATION : The CUC recommends that the Chandra Fellow's
>    office include clear statements about the importance of mentorship
>    in the letter that is sent to the host institutes of successful
>    candidates.  However, we recommend against a policy of requiring
>    mandated mentors.

CDO will include the paragraph (below) encouraging both the Fellow and
the Science Contact to make use of mentoring programs offered by the
host institution.  This paragraph will be inserted in the letter sent to
the Fellow, the Science Contact, and the host Grant Officer at the
time Fellows should be preparing to take up their Fellowships
(preparing budgets, etc.) 

"Chandra Fellows with the guidance of their Science Contacts have
produced outstanding work.  Since this stage is an important step in
building a career, we want to bring to your attention the value of
mentoring efforts by the host institution.  This is largely done
through interaction with the Science Contacts.  However, it is
sometimes useful to have a more ``arms length" view, and in some cases
a view from a different background.  We encourage host institutions to
foster mentoring during this transition from student to professional
status, and we ask that the Science Contact bring mentoring programs
and opportunities to the attention of the Fellows.  We also encourage
Chandra Fellows to develop a broad spectrum of collegial interactions."

>    continues to, support the Chandra Fellows Program in the strongest
>    possible terms.  It is without doubt considered one of the world's
>    most prestigious postdoctoral fellowships in astrophysics, and
>    supports (or has supported) many of the most successful young
>    high-energy astrophysicists in the country.  In addition to simple
>    name recognition, the importance of "community ownership" (in this
>    case, the high-energy astrophysics community) cannot be
>    underestimated... the Chandra Fellowship program is widely
>    acknowledged as the premier high-energy astrophysics fellowship
>    program, and the existence of this program is a crucial back-stop
>    in creating an optimistic environment for young high-energy
>    astrophysicists.  

NASA is reorganizing the Fellowship programs into the areas of NASA's
three science themes: Cosmic Origins, Physics of the Cosmos, and
Exoplanet Exploration The GLAST and Chandra Fellows programs will be
combined to form the Physics of the Cosmos program, called the
Einstein Fellowship Program.  This program will cover the full range
of science included in Physics of the Cosmos and will be
administered by the Chandra X-ray Center.  For the moment, two additional
Fellowships will be added to the combined Chandra and GLAST
Fellowships, making a total of 10 new awards each year (for the
standard expectation of 3 years).

> 7) CALIBRATION : As previously noted, the CUC was surprised to see a
>    significant HRMA calibration issue arise at this stage in the
>    mission.  However, once this issue was identified, the CUC has been
>    impressed by the response of the calibration team.
>    RECOMMENDATION : The CUC supports the ongoing efforts to solve the
>    HRMA effective area issue with high priority.  We also recommend
>    that steps are made to inform the community about this issue
>    (including a discussion of the kinds of scientific investigations
>    that could be affected by the calibration problem), possibly via
>    the newsletter or an email bulletin.

We have written a memo describing our cross-calibration efforts
with XMM-Newton on the derived gas temperatures for a sample
of clusters of galaxies.  This memo also describes our on-going
HRMA calibration efforts to properly account for the hydrocarbon
over layer that was present on the mirrors during the ground-based
tests at XRCF.  This memo has been posted on the CXC web site as
We will also include the memo in the next Chandra newsletter.

> 8) JOINT SUZAKU/CHANDRA OBSERVING TIME : The CUC recommends that the
>    CXC explore the possibility of a joint-time agreement with the
>    Suzaku program (such as currently exist with HST, XMM, Spitzer,
>    RXTE, NOAO and NRAO).  If such an agreement is possible, we suggest
>    that it be included in the CfP for Cycle-11.

Since the Suzaku mission is a US/Japan partnership, the logistics of
Suzaku donating time to a joint program are likely to be more complex
than with other joint partner observatories to date. As a first step,
CDO has initiated preliminary discussions with the U.S. Suzaku User
Committee about the possibility of a Joint program. 

> 9) CXC WEBSITE : The CUC feels that the CXC website
>    ( requires some general updating and
>    tidying.  The site seems to have evolved into four rather long and
>    unstructured lists of links.  We also suggest replacing the current
>    search engine with a modern commercial engine such as Google.

CDO has implemented a Google search engine, and revised and updated
a number of links on the current page.  CDO is committed to
a redesign and modernization of the front CDC pages.  The analysis of
whether and how the entire family of CXC webpages should be revised 
is complex.  A redesign would require significant coordination
between all groups, as well as redirection of resources from other
projects.  For this reason, CDO is forming a committee to evaluate
our options, even before any major changes to the frontpage are
implemented, for the sake of minimizing the number of changes to the
look-and-feel of the website for external users.

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